type bitCount = int
type range = int * int
val bits:range -> bitCount
val to_string:range -> string
val downto_string:range -> string
val ( --> ): int -> int -> range
val ( <-- ): int -> int -> range
val ( |-> ): int -> int -> range
val ( <-| ): int -> int -> range
val make_bits:int -> bitCount

val rebase: int->range->range
val normal: range->range


